Electrochromic Metallo-Organic Nanoscale Films: Fabrication, Color Range, and Devices

Abstract

In this study, we demonstrate a versatile approach for the formation of electrochromic nanoscale assemblies on transparent conductive oxides on both rigid and flexible substrates. Our method is based on the application of alternating spin-coated layers of well-defined metal polypyridyl complexes and a palladium(II) salt to form electrochemically addressable films with a high chromophore density. By varying the central metal ion of the polypyridyl complexes (Os, Ru, and Fe) and their ligands and by mixing these complexes, coatings with a wide range of colors can be achieved. These coatings cover a large area of RGB color space. The coloration intensities of these nanoscale films can be tuned by the number of deposition steps. The materials have very attractive ON/OFF ratios, electrochemical stabilities, and coloration efficiencies. Reversible color-to-colorless and color-to-color transitions were demonstrated, and the films were further integrated into sandwich cells.

Bifunctional Nanoscale Assemblies: Multistate Electrochromics Coupled with Charge Trapping and Release

“…Furthermore, the use of two different electrochromic layers would afford devices with new optical properties that cannot be obtained with monomolecular films. Several classes of electrochromic materials have been developed, ranging from transition metal oxides, polymers, and small organic molecules, to coordination complexes . For example, Hammond et al.…”

Bifunctional Nanoscale Assemblies: Multistate Electrochromics Coupled with Charge Trapping and Release

“…Furthermore, the use of two different electrochromic layers would afford devices with new optical properties that cannot be obtained with monomolecular films. Several classes of electrochromic materials have been developed, ranging from transition metal oxides, polymers, and small organic molecules, to coordination complexes . For example, Hammond et al.…”

“…Previously we have demonstrated the formation of surface‐bound metallo‐organic assemblies using LbL assembly as well as spin‐ and spray‐coating . Such materials have exceptional electrochromic properties . and have been used to mimic the operation characteristics of logic gates and even electronic circuits .…”

“…The bipy‐based ligands are functionalized with vinyl‐pyridyl moieties. These moieties are necessary for the formation of a dense coordination network on metal oxide surfaces with palladium dichloride . Owing to the structural similarity of complexes 1 and 2 , identical deposition conditions can be applied (Figure B).…”

A Multi‐Stimuli‐Responsive Oxazine Molecular Switch: A Strategy for the Design of Electrochromic Materials

“…[16,[18][19][20] Many efforts have been madet os olve these problems, [18,[21][22][23][24][25] and one promising methodi st oexploit new electrochromic materials. [26][27][28][29][30][31][32][33] Molecular switches represent ak ind of molecule with properties such as opticalp roperties, polarity,a nd solubility that can be changed when the structureo ft he molecule undergoes transformationu nder external stimuli, such as light, heat, pH, force, and electric fields. [34][35][36][37][38] Of these, pH-sensitive molec-ular switches are the most abundant and have wide applications in pH indicators,b iosensing, [39] and information communication.…”